The Castle of Unrelenting Terror is a large castle in Orpheus. Many dangers await those who dare to set foot inside the castle. Firstly, it tries to kill you with kindness. Jack and Prospero almost fall for this trick until Jack realizes the food isn't satisfying his hunger, and because Prospero is not suppost to have a reflection. Next, Jack scared a bunch of ghosts away simply by yelling at them, and lastly Jack had to defeat an evil doppelganger of himself using a clue provided by Lyra. This rewarded him with the Tiamond.